Christmas tree for wells



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CHRISTMAS TREE FOR WELLS Original Filed Dec. 9, 1964 ATTORNE Y5 on w 5 W MULW o Fm OMM I W 1.1/1 DH D Y N B M 5% WWW M H A A Mm 5 lo 5 f p :g u g.

United States Patent ()fiice 3,357,491 Patented Dec. 12, 1967 3,357,491 CHRISTMAS TREE FOR WELLS Marvin R. Jones, Leonard E. Williams, J12, and David L.

Gruller, Houston, Tex., assignors to Cameron Iron Works, Inc., Houston, Tex. Continuation t application Ser. No. 417,172, Dec. 9, 1964. This application May 11, 1967, Ser. No. 641,418

Claims. (Cl. 166-75) ABSTRACT OF THE DISCLOSURE In a Wellhead for underwater wells, a production bore is provided for connecting a flow line to the well tubing that extends into the well from the wellhead. The production bore has a substantially straight portion that extends upward vertically from the well tubing for a distance and a continuing outwardly curved portion for connection with the flow line. The curvature of the curved portion of the production bore and the flow line is such that well tools can be pumped through the flow line and production bore into and out of the well tubing. An auxiliary bore is provided in the wellhead to permit tools lowered on a wire line from the surface of the water to pass into and out of the well tubing. This service bore is connected to the straight portion of the production bore intermediate its ends and is curved outwardly and upwardly therefrom. Thus, well tools, being pumped out of the well, will tend to continue upwardly in a straight line and pass the entrance to the service bore. Tools lowered from the surface on a wire line through the service bore and into the well tubing, however, will be pulled back into the service bore as they pass upward through the straight portion of the production bore by the wire line to which they are attached.

This is a continuation of patent application Ser. No. 417,172, filed Dec. 9, 1964, and entitled Christmas Tree for Wells.

This invention relates to Christmas trees, generally, and it has particular application to Christmas trees located on or adjacent an earth surface underlying a body of water so that they are not readily accessible.

Usually a Christmas tree has one or more generally vertical production bores or passageways that are connected to one or more strings of flow tubing installed in a well and through which the well is produced. Certain operations, which are performed on the well after the Christmas tree is in place, such as swabbing, require vertical access to the flow tubing strings through the tree. Normally the tools for performing these operations are suspended on a wire line and run into and out of a tubing string through its associated production bore and a vertical riser extending vertically upward from the tree.

Certain other maintenance operations, however, can be performed by well tools which may be pumped into and out of a flow tubing string through its associated production bore and the flow line connected to the production bore. Performing maintenance operations in this manner is particularly useful in underwater wells. To allow fluid to be circulated freely into and out of the tubing string a service bore may be provided in the tree in fluid communication with the tubing string below the level to which such tools are pumped. Further, the flow line, through which the well tools are pumped into the production bore, curves tangentially upward therefrom to guide the pumped-in tools smoothly into and out of the production bore.

The flow line has hitherto been connected either into the side of the production bore or to its upper end. When it is connected to the upper end, it has to be removed when the vertical access to the tubing string associated with the production bore is desired. When the flow line is connected into the side of the production bore, it does not interfere with vertical access to the tubing string since the production bore extends above the point where the flow line is connected and can receive vertically lowered tools. Well tools, however, that are being pumped out of the tubing string, unless deflected when they reach the connection between the production bore and the flow line, will continue to travel upwardly through the generally vertical production bore, pass the entrance to the flow line, and enter the portion of the production bore thereabove. Thus, a removable deflector usually is post tioned in each production bore of such a tree, just above the entrance to the flow line connected thereto, to deflect pumped-in well tools traveling out of the well into the laterally curving flow line. Such deflector requires apparatus for orienting it and for locking it in place; and, in addition, it requires service equipment to remove it. Such apparatus is subject to mechanical failure. Further, the deflector may corrode, sand-up, or be otherwise fouled with foreign material to the extent that removal is difficult, particularly after the deflector has been installed in the tree for a long period of time.

Therefore, there is a need for a Christmas tree which will afford vertical access to a well and which will also allow well tools to be pumped into and out of a well through a laterally curved flow line without requiring a deflector to be installed in the tree; and it is an object of this invention to provide such a Christmas tree.

It is another object of this invention to provide a Christmas tree for a well, which affords vertical access to the well tubing through the production bore of the tree without requiring the flow line to be disconnected, that permits well tools to be pumped out of the well tubing into the flow line without requiring a diverter device to direct the tools into the flow line.

These and other objects, advantages, and features of this invention, will be apparent to those skilled in the art from a consideration of this specification and attached drawings.

These objectives are obtained in accordance with this invention by providing a Christmas tree for installation on a well, said tree having a production bore to provide fluid communication with and access to a string of well tubing through which such a well is produced. The production bore is connected to a flow line that curves laterally upward therefrom. The central axes of the production bore and flow line are substantially tangent at their point of connection; and both have sufficient radii of curvature to allow well tools to be pumped there through into and out of the well tubing. To permit vertical access to the well tubing through the tree, instead of extending the production bore above its connection with the flow line to allow well tools lowered vertically to enter its upper end and pass therethrough into the well tubing, as was done heretofore, an auxiliary bore is provided' in the tree that connects to the production bore intermediate its ends. This allows the upper end of the production bore to be connected directly to the flow line. Then, to insure that pumped-in well tools traveling out of the well through the production bore do not enter the auxiliary bore, the production bore immediately adjacent and above the connection of the auxiliary bore thereto is arranged more nearly in alignment with the production bore immediately below the connection than is the auxiliary bore adjacent the point of connection. Since pumped-in well tools traveling out of the well tubing into the production bore have inertia, they will tend to follow the path that requires the. least change in direction. Therefore, by arranging the portion of the production bore immediately above the connection of the two bores more nearly in line with the direction the tools are traveling when they reach that point, the tools will be caused to pass the entrance to the auxiliary bore and continue through the. production bore and into the flow line connected to the upper end thereof.

Well tools run into the well tubing through the vertical access auxiliary bore will travel through this bore to where it connects to the production bore and then through the portion of the production bore therebelow into the well tubing. These tools are normally run on a wire line. Therefore, as they move upwardly through the production bore upon being retrieved, they will be diverted into the auxiliary bore by the wire line when they reach the connection of the two bores. Thus, by providing a tree having bores arranged in this manner, no deflector device is required to keep the well tools traveling therethrough along the desired path.

The invention will now be described in detail in connection with the attached drawings, in which:

FIGURE 1 is a view, in elevation, but with parts broken away and shown in section, of an underwater wellhead assembly including a Christmas tree constructed in accordance with this invention having a production bore connected to. a flow line curving laterally upward from the tree, an auxiliary bore, and a service bore which in this embodiment is connected to a service line that also curves laterally upward from the tree; and

FIGURE 2 is an enlarged vertical sectional view of a portion of the Christmas tree of FIGURE 1 showing the connection of the production bore with the auxiliary bore and showing a pumped-in well tool in the production bore passing the entrance to the auxiliary bore.

The wellhead of FIGURE 1 is positioned adjacent earth surface 11, which is located under a body of water. It includes landing base 12, which is attached to surface casing 13. The landing base supports the surface casing until it is cemented in the ground in the conventional manner. Attached to surface casing 13 and supported thereby iscasing head 14 from which is suspended inner or production casing string 15 and tubing strings 16 and 17.

Releasably attached to the casing head by collet type connector 19 is Christmas tree 20. Any type of releasable connector can be used; the type shown is described in United States Patent No. 3,137,348. Christmas tree 20 includes valve block 21, in which master valves 22 and 23 are located, body 24, and flow wings 25 and 26 including wing valves 27 and 28. Also forming part of the Christmas tree is swabbingvalve 29 located in body 24. The tree can, of course, be arranged in, a variety of ways. For example, the wing valves may be located in body 24, which may consist of several pieces connected together.

In the embodiment shown, Christmas tree 20 is designed for a well having only one producing string of tubing. Therefore, it is provided with first, passage means comprising production bore 30 having an upwardly ex-.

tending substantially straight portion and a continuing outwardly curved portion for connection to a flow line for conveying fluid from the well and also for conveying well tools. The production bore is connected to tubing string 17 through valve block 21 and master valve 23, in a manner well known in the art, to provide a continuous passageway through which fluid and well tools can freely pass between bore 30 and tubing string 17, when master valve 23 is open.

The production bore extends upwardly from its connection with tubing string 17 through body 24, through flow wing 26, and is connected at its upper end to flow line 31 by wing valve 28. The bore has an upwardly extending substantially straight lower portion 30a with a generally vertical longitudinal axis, and a continuing outwardly curved upper portion 30b which preferably curves.

with substantially the same radius of curvature as the end of the flow line to which it is connected.

The lower portion and the upper portion of the production bore are joined together to provide a continuous smooth-walled bore at their connection. In other words, their connection should be such the transition of a well tool between the generally straight lower portion and the curved upper portion is gradual with no abrupt changes in direction.

The radius of curvature of both the upper portion of the production bore and the end of the flow line should be sufficient to allow the passage of the presently available well tools designed to be pumped into and out of a well. For example, for a flow line with a nominal diameter of two inches, a radius of curvature of five feet is considered to be the minimum that will pass presently available pump-in tools of this size.

When well tools are to be pumped into and out of tubing string 17 through production bore 30 and flow line 31, usually, means are provided for pumping into the tubing string below the tool to force the well tool back out of the well along the same path. In tree 20,

wardly from its connection with tubing string 16 in valve block 21, through body 24 and valve 35 to provide vertical access to tubing string 16. Service line 33 is connected to service bore 32 through flow wing 25 and wing valve 27. Both the flow wing and the service line are I curved to allow well tools to be pumped into and out of tubing string 16. Thus, as shown, the bore of the flow wing intersects the service bore with its central axis tangent to the longitudinal axis of the service bore.

Vertical access to tubing string 17 through tree 20 is provided by second passage means which branches upwardly and outwardly from a point intermediate the substantially straight portion of the first passage means. In the embodiment shown, the second passage means comprises auxiliary bore 34 located in body 24 of the tree. Bore 34 has upper portion 34a, which extends generally vertically through body 24 to provide an upwardly extending opening to receive well tools lowered vertically.

from a drilling vessel or platform on the surface of the water. The longitudinal axis of portion 34a is generally parallel to but laterally offset from the generally vertical longitudinal axis of lower portion 30a of production bore 30. The upper portion of the auxiliary bore is connected to lower portion 30a oi the production bore by a reversely curved lower portion 34b. Preferably, the two bores arev connected together at a point below the connection of the substantially straight lower portion of the production bore with its curved upper portion.

In accordance with this invention the portion of the production bore immediately adjacent and above the connection between the two bores is more nearly in alignment with the portion of the production bore immediately adjacent and below the connection than is the por-- tion of the auxiliary bore immediately adjacent the .connection. Thus, in the embodiment shown, the portions of the production bore on-each side of the connection are substantially straight and in axial alignment whereas,

the portion of the auxiliary bore adjacent the connection curves laterally out of alignment with the portion of the production bore below the connection. Thus, well tools being pumped out of well tubing 17 will be traveling generally vertically upward as they approach the con nection between the two bores. Due to their inertia and possibly also to continued guidance by engagement with lower portion 30a of the production bore, the. well tools.

will tend to continue traveling vertically upward through portion 30:: and pass the entrance to the auxiliary bore. The upper portion of the production bore will then direct the tools into the flow line. Thus, no deflector device is required to keep the pumped-in tools out of the auxiliary, vertical access bore.

The reversely curved lower portion 34b of the auxiliary bore should have sufficient radii of curvature to provide a tool-carrying connection between the upper portion of the bore and the production bore. The radii of curvature need not be the same but the smallest should be sufliciently large to allow the passage of presently available wire line suspended tools for running into well tubing. Also, preferably the reversely curved portion is substantially tangent to the longitudinal axes of both the upper portion of the auxiliary bore and the lower portion of the production bore where connected thereto, to provide a continuous smooth-walled bore through the auxiliary bore into the production bore.

Well tools run into and out of the hole through the flow line should, of course, be provided with sufficient sealing members spaced far enough apart to bridge the connection between the production and auxiliary bores. Otherwise, it is possible that the tools could stall at this connection, since it allows fluid to by-pass the sealing members due to the enlarged common bore. For example, as shown in FIGURE 2, well tool 40 is provided with oppositely facing cups 41 and 42 on one end and 43 and 44 on the other end. These cups are spaced sufiiciently for one set, for example, cups 41 and 42 to be in sealing engagement with bore 30 beyond its connection with bore 34 before sealing cups 43 and 44 enter the connection, as the tool is traveling out of the well. The reverse is true when the tool is being pumped into the well bore.

Although the above described Christmas tree has only one production bore, it is understood, of course, that any number of production bores with associated auxiliary bores can be provided.

From the foregoing, it will be seen that this invention is one Well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus and structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

1. A wellhead member adapted to control the path of tools pumped from a well, comprising first passage means providing a production bore having an upwardly extending substantially straight portion and a continuing outwardly curved portion for connection to a flow line for conveying fluid from the well and also for conveying said tools therefrom, and second passage means providing an auxiliary bore branching upwardly and outwardly from a point intermediate said straight portion of the production bore and continuing upwardly, said second passage means, during normal well production, being free from a retrievable deflector means, whereby access to the well may be had through the second passage means but tools pumped from the well will follow said first passage means.

2. A Christmas tree including a body having a production bore for conveying fluid from a well to a flow line and for conveying pumped well tools into and out of the well, and an auxiliary bore having a connection to the production bore intermediate the ends of the latter and extending generally upwardly therefrom for conveying v. 6 wire line suspended well tools to the connection to said production bore and thence through the production bore into the well, and for retrieval thereof by such wire line, the production bore adjacent and above the connection of the auxiliary bore thereto being more nearly in alignment with the production bore below and adjacent said connection than is the auxiliary bore adjacent said connection, said auxiliary bore, during normal well production, being free from retrievable reflector means; whereby tools being pumped out of the well through said production bore will follow said production bore past said connection, and tools being retrieved from the well by a wire line extending through said auxiliary bore into the production bore and thence into the well to the tool being retrieved will be deflected by such wire line into the auxiliary bore.

3. The Christmas tree as defined in claim 2 in which the production bore has, substantially straight longitudinal axes adjacent to and on either side of the connection so a well tool being pumped out of the well through the production bore will travel along substantially a straight line 7 when passing the connection of the two bores.

4. The Christmas tree of claim 2 in which the auxiliary bore has an upper portion whose longitudinal axis is laterally offset from and substantially parallel to the longitudinal axis of the production bore at the connection and a reversely-curved lower portion providing a tool-conveying connection between the auxiliary bore and the production bore and disposed substantially tangent to both.

5. The Christmas tree of claim 2 in which the production bore curves laterally above its connection with the 1auxiliary bore for connection to a laterally-extending fiow 6. A Christmas tree including a body having a production bore for conveying fluid from a well to a flow line and for conveying pumped well tools into and out of such well, a service bore for connection to such well to allow fluid to be circulated into and out of such well between the service bore and the production bore to pump well tools into and out of such well through the production bore, and an auxiliary bore having a connection to the production bore intermediate the ends of the latter for conveying wire line suspended well tools to the point of connection to said production bore and, thence, through the production bore into such well, the production bore immediately adjacent and above the connection of the auxiliary bore thereto being more nearly in alignment with the production bore immediately below and adjacent said connection than is the auxiliary bore immediately adacent said point, said auxiliary bore, during normal well production, being free from retrievable reflector means; whereby tools being pumped out of such well through sa d production bore will follow said production bore past said connection, and wire line suspended tools run into the well through the auxiliary and production bore will be deflected by the wire line from the production bore into the auxiliary bore at their connection as the tool is being pulled from such well by the wire line.

7 A Christmas tree having a production bore and an auxiliary bore through which well tools can pass into and out of a well, said production bore having a lower portion with a generally vertical longitudinal axis and a laterally-curving upper portion smoothly joined thereto to provide a continuous smooth well bore for connection to a flow line, said auxiliary bore having an upper portion, whose longitudinal axis is laterally offset from the longitudinal axis of the lower portion of the production bore and generally vertical, and a reversely-curved lower portion providing a tool-conveying connection between the upper portion of the auxiliary bore and the lower portion of the production bore, and disposed substantially tangent to both.

8. The Christmas tree of claim 7 in which the longitudinal axis of the production bore is substantially straight adjacent to and on either side of the connection between the production bore and the auxiliary bore.

9. The Christmas tree of claim 7 in which the longitudinal axis of the upper portion of the auxiliary bore is substantially parallel to the longitudinal axis of the lower portion of the production bore.

10. A Christmas tree having a production bore for conveying fluid from a well to a flow line and for conveying well tools pumped through such flow line into and out of such well, a service bore for connection to such well to allow fluid to be circulated into and out of the well between the service bore and the production bore to pump well tools into and out of such well through the production bore, and an auxiliary bore connected to the production bore for conveying wire line suspended well tools to the connection to said production bore; said production bore having a lower portion with a generally vertical 1ongitudinal axis and a laterally curving upper portion smoothly joined thereto to provide a continuous smooth well bore for connection to a flow line, said auxiliary bore having an upper portion,whose longitudinal axis is laterally offset from the longitudinal axis of the lower portion of the production bore and generally vertical, and a reversely-curved lower portion providing a tool conveying connection between the upper portion of the auxiliary bore and the lower portion of the production bore and disposed substantially tangent to both, whereby well tools being pumped out of such well through the production bore will follow the production bore past the connection between the production and auxiliary bores, and wire line suspended tools lowered into such well through the auxiliary bore and the portion of the production bore below the connection therebetween will be deflected by the wire line from the production bore into the auxiliary bore as the tools are being retrieved.

References Cited UNITED STATES PATENTS 2,810,442 10/1957 Tausch 166.5 X 3,003,560 10/1961 Corley et al. 166-.5 X 3,022,822 2/1962 McStravick ct al. 166.5 X 3,055,429 9/1962 Tausch et al. 166-46 X 3,064,735 11/1962 Bauer et al 166-75 3,139,932 7/1964 Johnston 166-.5 3,260,270 7/1966 Watkins et al. 166-.5 X

CHARLES E. OCONNELL, Primary Examiner.

R; E. FAVREAU, Assistant Examiner. 

1. A WELLHEAD MEMBER ADAPTED TO CONTROL THE PATH OF TOOLS PUMPED FROM A WELL, COMPRISING FRIST PASSAGE MEANS PROVIDING A PRODUCTION BORE HAVING AN UPWARDLY EXTENDING SUBSTANTIALLY STRAIGHT PORTION AND CONTINUING OUTWARDLY CURVED PORTION FOR CONNECTION TO A FLOW LINE FOR CONVEYING FLUID FROM THE WELL AND ALSO FOR CONVEYING SAID TOOLS THEREFROM, AND SECOND PASSAGE MEANS PROVIDING AN AUXILIARY BORE BRANCHING UPWARDLY AND OUTWARDLY FROM A POINT INTERMEDIATE SAID STRAIGHT PORTION OF THE PRODUCTION BORE AND CONTINUING UPWARDLY, SAID SECOND PASSAGE MEANS, DURING NORMAL WELL PRODUCTION, BEING FREE FROM A RETRIEVABLE DEFLECTOR MEANS, WHEREBY ACCESS TO THE WELL MAY BE HAD THROUGH THE SECOND PASSAGE MEANS BUT TOOLS PUMPED FROM THE WELL WILL FOLLOW SAID FIRST PASSAGE MEANS. 